JPH0987757A - Operation of flash smelting furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the unevenness of matte quality and molten ore temp. by controlling the air quantity for reaction and auxiliary fuel quantity while following up the variation of supplying quantity accompanying the variation of bulk density of dried ore into a flash smelting furnace. SOLUTION: An average dried ore bulk density ρi for each Δt min at each Δt min of a desired fixed time is measured with a bulk density meter fitted to a dried ore discharging part of a dried ore storage arranged at the upper part of a reaction tower of the flash smelting furnace. The variation quantity of the dried ore supplying quantity for Δt min from the time ti-1 when measuring ρi-1 by using the equation based on this average dried ore bulk density ρi , the average dried ore bulk density ρi-1 at the previous time and a target value W (ton/hr) of the dried ore supplying quantity at this time to the time ti , is considered as ΔW (ton/hr). In this equation, K is correction factor in the range of 0.1<=K<=1. The setting values of the air quantity and the auxiliary fuel quantity at the time ti-1 when supplied into the flash smelting furnace caused by this ΔW are corrected to be the setting values at the time ti . Thereafter, at each measurement, the setting values of the air quantity and the auxiliary fuel quantity are corrected.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method of operating a flash furnace used for smelting non-ferrous metals.

[0002]

2. Description of the Related Art As one of non-ferrous metal smelting methods using a sulfide concentrate, there is a flash smelting method. In the flash smelting method, a powder burner such as sulfide concentrate, flux, smoke ash, etc., and reaction air are blown into the reaction tower from a concentrate burner provided at the top of the reaction tower of the flash furnace to melt them. . Then, the valuable metal is concentrated as a river and the other components are separated as a kelami and a gas.

In order to operate this flash smelting smelting method efficiently, it is necessary to mix various brands of concentrates and auxiliary raw materials such as flux and dry them before supplying various raw materials to the furnace. is necessary. Therefore, these raw materials are cut out from the storage bottle in an undried state, mixed, and then supplied to a drying facility. Next, the dried smelting raw material (hereinafter referred to as dry ore) obtained in the drying equipment is supplied to the dry ore storage provided at the upper part of the reaction tower of the flash furnace, and further cut out from the dry ore storage by a chain conveyor or the like, It is being supplied into the flash furnace. At this time, the amount of dry ore, the amount of reaction air, and the amount of auxiliary fuel supplied into the furnace are set in consideration of the physical quantity balance and the heat balance.

In actual operation, it is important to maintain these set values accurately. For example, if the amount of dry ore supplied is too large for a given amount of reaction air and auxiliary fuel, the quality of the Kawa is degraded. In addition, the temperatures of the molten kawa and the kelami are lowered, and the viscosity of the kelami becomes high, which makes it difficult to discharge the kelami to the outside of the furnace. Conversely, if the amount of dry ore supplied is too small, the quality of the river will increase. In addition, the temperature of the river and the kelami rises, causing the brick to melt. Furthermore, if the quality of the Kawa is uneven, it will cause a great obstacle to the stable operation even in the converter, which is a lower process.

Recently, the reaction air amount and auxiliary fuel amount set in consideration of the physical quantity balance and the heat balance are set accurately by using a highly accurate flow meter or flow controller. It is possible to maintain

On the other hand, for dry ore, Japanese Patent Laid-Open No. 7-4863
No. 3 gazette proposes a method for adjusting the dry ore supply amount.
That is, the amount of undried raw material supplied from the ore storage bin to the drying equipment and the amount of dry ore in the dry ore storage while the dry ore is being supplied to the flash smelting furnace are measured at desired fixed intervals. This is a method of adjusting the dry ore supply rate by correcting the dry ore supply rate by a chain conveyor or the like based on the calculation formula from these measured values.

By adopting the method described in this publication, the amount of dry ore supplied can be adjusted more accurately than in the past. However, when quantitatively cutting out the dry ore using a chain conveyor, etc., the volume of the dry ore is controlled as a standard, so it is possible to avoid fluctuations in the dry ore supply amount due to changes in the bulk density of the dry ore. There wasn't. Therefore, even if the amount of reaction air and the amount of auxiliary fuel are accurately maintained at the set values, there is a certain limit to the reduction in the variation of the quality and the melt temperature.

[0008]

SUMMARY OF THE INVENTION The present invention controls the amount of reaction air and the amount of auxiliary fuel in accordance with the fluctuation of the supply amount of the dry ore to the flash smelting furnace due to the fluctuation of the bulk density of the dry ore, thereby controlling the quality and melting of the slag An object of the present invention is to provide a method for operating a flash furnace that reduces variations in body temperature.

[0009]

[Means for Solving the Problem] Undried smelting raw material is cut out from a storage bin, the smelting raw material is dried in a drying facility, and the obtained dry ore is a dry ore provided in the upper part of a reaction tower of a flash furnace. Supply to the warehouse. The dry ore is continuously supplied from the dry ore cutting section of the dry ore warehouse to the flash furnace by using a chain conveyor or the like. A non-contact bulk density meter is attached to the dry ore cutting portion, and the average dry ore bulk density ρ _i for each Δt minutes is measured at each time t _i divided by a desired fixed time interval Δt minutes.

From this average dry ore bulk density ρ _i , the previous average dry ore bulk density ρ _{i -1,} and the target value W (tons / hour) of the dry ore supply amount at this time, using Equation 2, Previous average dry bulk density ρ
the _i-1 from the time t _i-1 was measured, the amount of variation of dry ore supply amount of △ t minutes to t _i △ W regarded as a (ton / hr).

[0011]

In Equation 2] △ W = k · W (ρ i over _{ρ i-1) / ρ i} -1 number 2 k is an correction factor takes a 0.1 value of ≦ k ≦ 1.

The correction values of the air amount and the auxiliary fuel amount for correcting the difference between the quality of the Kawa and the temperature of the Kawa and the Karami due to the ΔW are determined based on the physical quantity balance and the heat balance. To do.

In the method for operating a flash furnace according to the present invention, the correction values are added to or subtracted from the set values of the air amount and the auxiliary fuel amount at the time t _i-1 to correct the set values, and the set values at the time t _i are set. And After that, the flash furnace is operated with the feature that the set values of the air amount and the auxiliary fuel amount are corrected each time the measurement is performed.

Further, in the method for operating a flash furnace according to the present invention, in the above method, the constant time interval Δt is 1-6.
It is set to 0 minutes, preferably 5 to 20 minutes.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for operating a flash furnace according to the present invention, the amount of fluctuations ΔW in the amount of dry ore supplied is calculated from the average dry ore bulk density for Δt minutes, and the amount of air and the amount of auxiliary fuel are changed. The reason for changing the air amount and the auxiliary fuel amount by following the fluctuation of the dry ore supply amount is that it is difficult to maintain the dry ore supply amount accurately, but the air amount and the auxiliary fuel amount are accurately supplied. This is because the amount can be controlled.

In the present invention, the value for Δt minutes is 1 to 6
It is set to 0 minutes, preferably 5 to 20 minutes. The reason for this is
This is because if the value for Δt minutes is 1 minute or less, there is a high risk that the amount of air or the amount of auxiliary fuel will be changed more than necessary due to the effect of instantaneous fluctuations in bulk density. On the contrary, if the value of Δt minutes is set to 60 minutes or more, even if the air amount and the auxiliary fuel amount are changed in accordance with the fluctuation of the dry ore supply amount, the melt in the furnace has already been completely replaced. This is because it causes the reactor condition to deteriorate extremely.

Further, even when the value of Δt minutes is set as a preferable condition in the present invention, that is, 5 to 20 minutes, a mixture of concentrates of various brands in the drying step or an auxiliary raw material such as silicate ore is used. If the mixture with and is not sufficient, the bulk density may fluctuate greatly.

The correction coefficient k is introduced as a means for avoiding the risk of changing the air amount or the auxiliary fuel amount more than necessary due to the change in the bulk density due to the above-mentioned causes.
Due to the above reasons, the bulk density may fluctuate greatly,
When fluctuation is expected, the value of k is set relatively small, for example, 0.2 to 0.3. By making the value of k relatively small, it is possible to avoid the risk of changing the air amount or the auxiliary fuel amount more than necessary.

On the other hand, when the fluctuation of the bulk density is small and the dry ore supply amount is stable, the value of k may be relatively large, for example, 0.8 to 1.0. By making the value of k relatively large, the amount of air for reaction and the amount of auxiliary fuel can be controlled with higher accuracy by following the fluctuations in the supply amount of dry ore to the flash furnace, and the quality of the melt and the melt temperature can be controlled. It is possible to operate a flash furnace to reduce variations.

[0020]

[Embodiment] Inner size: width 6 m, length 20 m, effective volume 50 m
^A test operation was carried out by the method according to the present invention in a flash furnace having ³ liquid pools and a reaction tower having a diameter of 6 m and a height of 6.5 m. In this test operation, the operation method according to the present invention was further carried out after the method for adjusting the dry ore supply amount described in JP-A-7-48663 was carried out.

In this test operation, Δt = 15 minutes, k
= 1. Other operating conditions are as follows.

Dry ore supply amount 90 tons / hour Auxiliary fuel (heavy oil) supply amount 300 liters / hour Reaction air amount 33,000 Nm ³ / hour Oxygen enrichment rate 43% Target Kawa quality 62% Fe / SiO _{2 in} Karami 1.05 Before carrying out the test operation according to the present invention, first, the operation for carrying out the method for adjusting the dry ore supply amount by the conventional method (the method described in JP-A-7-48633) was carried out for 3 days,
During this period, the Kawa quality, the Kawa temperature, and the Karami temperature were measured 23 times. As a result, the average Kawa grade is 62.21%,
The standard deviation is 0.74%, and the average Kawa temperature is 123.
The temperature was 2.1 ° C., the standard deviation was 7.3 ° C., the average carami temperature was 1233.8 ° C., and the standard deviation was 8.5 ° C.

Next, a test operation was carried out for 3 days by carrying out the method for adjusting the feed rate of dry ore as described above and further carrying out the method according to the present invention. During this period, the Kawa quality, the Kawa temperature, and the Karami temperature were measured 25 times. As a result, the average kawa quality was 62.05%, the standard deviation was 0.61%, the average kawa temperature was 1230.3 ° C, and the standard deviation was
6.2 degrees Celsius, the average Karami temperature is 1234.1 degrees Celsius,
The standard deviation was 7.3 ° C.

Comparing these operation results, by carrying out the method according to the present invention, the average kawa quality becomes closer to the target quality as compared with the conventional method, and the kawa quality, the kawa temperature and the karami temperature are standard. The deviation was reduced, and it was possible to suppress variations in the quality and the melt temperature.

That is, the fluctuation of the dry ore supply amount is detected from the measured value of the bulk density, and the air amount and the auxiliary fuel amount are controlled in accordance with the change of the dry ore supply amount, so that a stable flash smelting furnace can be operated. It turned out that the furnace condition was obtained.

[0026]

As described above, according to the method for operating a flash furnace according to the present invention, it is possible to suppress the variations in the quality of the powder and the melt temperature and stabilize the furnace condition of the flash furnace.

Claims (2)

[Claims] 1. A facility for continuously supplying dry ore from a dry ore storage to a flash furnace, and measuring an average dry ore bulk density ρ _i for each Δt minute at desired fixed time intervals Δt minutes. When the target value of the dry ore supply amount at this time is W (ton / hour), the time t _i-1 to t _i at which the previous average dry ore bulk density ρ _i-1 was measured
Δt for the fluctuation amount of dry ore supply for t minutes
Assuming that W (ton / hour), the set values of the air amount and the auxiliary fuel amount at the time t _i-1 supplied to the flash furnace due to this ΔW are corrected to be the set values at the time t _i . A method for operating a flash smelting furnace, characterized in that the set values of the air amount and the auxiliary fuel amount are corrected each time. In Equation 1] △ W = k · W (ρ i over _{ρ i-1) / ρ i} -1 number 1 k is an correction factor takes a 0.1 value of ≦ k ≦ 1. 2. The method for operating a flash furnace according to claim 1, wherein Δt is 1 to 60 minutes.